Kevin Bright teased several details of the programme during an interview on the Better Together with Maria Menounos podcast.
The reunion was originally supposed to be available by the time HBO Max launches in the US, on 27 May.
However, the coronavirus crisis, which has forced many programmes to halt production, has made it impossible to stick to that schedule.
Menounos asked Bright for an update on the release schedule, to which he replied: “We’re just waiting. We’re waiting for a window. We feel the reunion needs to be done in front of an audience. We can’t not share it after all this time.
“So, tentatively speaking, we’re hoping that the special will be completed by Thanksgiving and that the show will be seen on HBO Max at that time.”
Bright also said the unscripted episode will consist in “a reunion of the cast getting nostalgic about the show”.
“It’s not them putting on the old characters and doing a new version of Friends,” he added.
The special will include some never-before-seen footage, such as alternative takes of famous scenes, Bright teased.
“We have every piece of footage we ever shot on Friends,” he said.
Bob Greenblatt, the chairman of WarnerMedia Entertainment (HBO Max’s parent company), recently said the team behind the special hope to film it by the end of summer.
The Friends finale aired on 6 May 2004 and was watched by an estimated 52.5 million people in the US.
HBO Max’s special will mark the first time all six stars – Jennifer Aniston, Courteney Cox, Lisa Kudrow, David Schimmer, Matt LeBlanc, and Matthew Perry – reunite in front of the cameras.